KR100787525B1 - 6 Mirror-microlithography-projection objective - Google Patents

Abstract

The present invention includes an entrance pupil and an exit pupil for imaging an object field in an image field, the image field forming segments of a ring field, the segments having a width perpendicular to the axis of symmetry and the axis of symmetry, the width being First (S1), second (S2), third (S3), fourth (S4), fifth (S5), and sixth mirrors at least 20, preferably 25 mm, arranged concentrically with respect to the optical axis (S6), each of the mirrors relates to a short wavelength microlithography projection objective, in particular having an effective range in which light beams guided through the projection objective are hit.

The present invention is characterized in that the diameter of the effective range of the first, second, third, fourth, fifth and sixth mirrors is ≤ 1200 mm * NA depending on the numerical aperture NA in the exit pupil.

Description

6 Mirror-microlithography-projection objective}

The present invention relates to a microlithographic objective lens according to the preamble of claim 1, a projection exposure apparatus according to claim 23, and a chip manufacturing method according to claim 24.

Lithography with wavelength <193 nm, in particular EUV-lithography with λ = 11 nm or λ = 13 nm, is referred to as a possible technique for imaging structures <130 nm, in particular <100 nm. The resolution of the lithography system is represented by the following equation:

RES = k ₁ ㆍ

Where k1 is the intrinsic parameter of the lithographic process, λ is the wavelength of incident light, and NA is the numerical aperture of both sides of the system.

In the imaging system in the EUV-range, a multilayer reflective system is used as the optical element. As a multilayer system, Mo / Be-system at λ = 11 nm and Mo / Si system at λ = 13 nm are used.

Based on the numerical aperture of 0.2, the imaging of a 50 nm structure by 13 nm light requires a relatively simple process with k ₁ = 0.77. At 11 nm light, k ₁ = 0.64 allows imaging of 35 nm structures.

Since the reflectivity of the multilayers used is in the range of about 70%,

In projection objectives for microlithography, it is very important to obtain sufficient light intensity with as few optical elements as possible.

In view of high light intensity and sufficient possibility for correction of imaging errors, a 6 mirror NA = 0.20 system has been found to be particularly desirable.

6 mirror systems for microlithography are described in publications US-A-5 153 898, EP-A-0 252 734, EP-A-0 947 882, US-A-5686728, EP 0 779 528, US 5 815 310, WO 99 / 57606 and US 6 033 079.

The projection lithography system according to US-A-5 686 728 is a projection objective with six mirrors, each reflecting mirror surface being formed as an aspherical surface. The mirrors are arranged along the common optical axis so that an optical path without obscuration is obtained.

Since the projection objective known from US-A-5 686 728 is used only for UV-light with a wavelength of 100-300 nm, the mirrors of the projection objective are very high aspherical and about +/- 50 μm. It has a very large angle of incidence of 38 °. Even after shielding with NA = 0.2, an aspherical surface of 25 mu m is maintained per peak and the angle of incidence is not reduced. These aspherical surfaces and angles of incidence are not practical due to the high demands on the surface quality, reflectivity of the mirror in the EUV-range.

A disadvantage of the objective known from US-A-5 686 728 is that it can no longer be used in the range of λ <100 nm, especially in the wavelengths of 11 and 13 nm, and the distance between the wafer and the mirror closest to the wafer is very large. It is small. At the distance between the wafer and the mirror closest to the wafer, known from US-A-5 686 728, the mirror can only be formed very thin. However, due to the extreme layer stress in multilayer systems for wavelengths of 11 and 13 nm, mirrors in this manner are very unstable.

EP-A-0 779 528 is known projection objectives with six mirrors for use in EUV-lithography, in particular at wavelengths of 13 nm and 11 nm.

The projection objective has the disadvantage that at least two of the six mirrors in total have a very high aspherical surface of 26 or 18.5 μm. In particular, in the apparatus known from EP-A-0779528, the light working distance between the mirror closest to the wafer and the wafer is small, resulting in instability or negative mechanical working distance.

WO 99/57606 discloses six mirror-projection objectives for EUV-lithography with a concave-convex-convex-concave-convex-concave mirror order. The objective lens has a numerical aperture NA _Objekt = 0.2 in the object. All mirrors of the system known from WO 99/57606 are formed aspheric.

A disadvantage of the six mirror-objective known from WO 99/57606 is that no easy accessibility of the effective range for inserting the second mirror and the third mirror is given, in particular. In addition, in the system known from WO 99/57606, the effective range of the fourth mirror is widely arranged outside the optical axis. This causes problems with the stability of the mirror system and with the manufacturing of the mirror segment. In addition, to encapsulate the system, a large retrofit space is required. Since the system is used in a vacuum, a relatively large space must be evacuated. The aperture disposed between the second and third mirrors according to WO 99/57606 results in an angle of incidence on the third mirror, in particular greater than 18 °.

In US 6033079 a six mirror-system is known, in which the angle of incidence for all mirrors is less than 18 °. However, the system also does not approach the effective range of the third mirror, and the effective range of the individual mirrors, for example the fourth mirror M4, is large and requires a large retrofit space as in the system known in WO 99/57606, This also has the disadvantage that the space to be evacuated is relatively large. Another disadvantage of relatively large mirrors is the lack of stability and the fact that a correspondingly large coating chamber and manufacturing machine are required in the manufacture.

The object of the present invention is in particular suitable for lithography with short wavelengths of less than 100 nm, without the disadvantages of the prior art described above, characterized by the smallest possible dimensions, good accessibility of the respective mirror's effective range, and as large as possible It is to provide a projection objective lens with the possibility of correcting as much as possible about opening and imaging errors.

The object comprises an entrance pupil and an exit pupil for projecting an object field in the object plane into an image field representing a segment of the ring field in the image plane according to the invention, wherein the segment is an axis of symmetry. And first, second, third, fourth, fifth and sixth mirrors having a width perpendicular to the axis of symmetry, the width being at least 20, preferably 25 mm, and arranged concentrically with respect to the optical axis. Each of the mirrors has an effective range in which light rays guided through the projection objective lens collide, and the diameters of the effective ranges of the first, second, third, fourth, fifth, and sixth mirrors are determined in the exit pupil. ≤ 1200 mm * NA, preferably ≤ 300 mm, depending on the numerical aperture NA of. The numerical aperture NA in the exit pupil of the objective lens according to the invention is 0.1, preferably 0.2, particularly preferably greater than 0.23. , Especially for short wavelengths less than or equal to 193 nm Achieved by microlithographic projection objectives. In the present application, the numerical aperture in the exit pupil means the numerical aperture of the light beam striking the image plane, the so-called upper plane numerical aperture.

In the category of microlithography, it is desirable for the imaging light beam to telecentrically strike the image plane. In that case, it is preferable that the sixth mirror S6 of the projection objective lens is formed concave. The fifth mirror S5 lies between the sixth mirror S6 and the image plane.

In order to implement the shadowless optical path in the objective lens of the above-described method, the objective lens affects the numerical aperture NA at the exit pupil.

In the preferred embodiment, the average radius of the ring field to be imaged is also increased with increasing numerical aperture in the exit pupil, thereby realizing a shadowless optical path in the objective lens.

In a preferred embodiment, the first, second, third, fourth, fifth and sixth mirrors each have a rear construction space, the space measured in the effective range along the optical axis from the mirror front face to achieve a predetermined depth. That is, the depth of the first, second, third, fourth and sixth construction spaces is at least 50 mm, and the depth of the construction spaces of the fifth mirror is greater than one third of the diameter value of the fifth mirror, respectively. By not allowing the constituent spaces of s to intrude into each other, in particular, accessibility to the individual mirrors of the objective lens for inserting the mirrors is given.

In terms of accessibility, it is particularly preferred that all constituent spaces can extend in a direction parallel to the axis of symmetry, without crossing the space of another mirror or the optical path in the objective lens.

If the boundary area surrounding the effective range of all mirrors is larger than 4 mm, and light is guided without shading in the objective lens, a particularly stable system is obtained in terms of edge deformation induced by layer stress.

Coating of mirror substrates with the Mo / Be or Mo / Si-multilayer systems described above often results in stresses that can cause deformation, particularly at the edges of the substrate. A sufficiently large boundary area prevents the stress from extending into the effective range of the mirror.

In a preferred embodiment, the effective range of the fourth mirror lies geometrically between the second mirror and the image plane.

It is particularly preferred that the fourth mirror is geometrically arranged between the third mirror and the second mirror, in particular between the first mirror and the second mirror. This arrangement results in very small dimensions of the effective range of the first, second, third and fourth mirrors.

The distance S4 S1 of the vertex of the fourth mirror and the first mirror along the optical axis is preferably the distance S2 S1 of the second mirror and the first mirror.

0.1 < <0.9

The distance between the third mirror and the second mirror (S2 S3) vs. the distance between the fourth mirror and the third mirror (S3 S4)

0.3 < <0.9

Lies in the range of.

For the shadowless light path, two critical regions are given, in particular in the objective lens portion comprising the fifth and sixth mirrors.

One critical region lies at the upper edge of the fifth mirror. There, the light guide must be such that the lower edge light beam extends above the effective range of the mirror and impinges on the image plane. Another critical region lies at the bottom edge of the sixth mirror.

The average ring field radius R is the numerical aperture NA at the exit pupil, the distance between the vertices of the fifth mirror and the sixth mirror (S5 S6), the distance between the fifth mirror and the image plane (S5B), of the fifth or sixth mirror. If the radius of curvature r ₅ , r ₆ is selected according to the following equation,

Shadowless ray guides in the region of the fifth and sixth mirrors are approximated paraxially. When maintaining the condition of the light guide without shading, undershoot of the minimum radius raises the aspherical deviation from the spherical basic shape of the mirror, also called the aspherical surface of the mirror, in a jump form. This applies in particular to the fifth mirror. Thus, the paraxial approximation and the area to which the above-described formula is applied disappear. However, mirrors with high aspherical surface can only be manufactured at high cost due to manufacturing techniques.

In order to keep less of each load in the mirror, it is desirable that the incident angle of the chief ray of the field point centered on the object field in the axis of symmetry is less than 18 ° for all mirrors.

In a particular embodiment of the invention, the projection objective has an intermediate image, which intermediate image is preferably formed after the fourth mirror in the light direction in the projection objective.

In the first embodiment of the present invention, the first mirror is convex and a total of six mirrors are formed aspheric.

In another embodiment of the present invention, the first mirror is concave, and a total of six mirrors are formed aspherical.

As an alternative, the first mirror may be formed in the paraxial plane and a total of six mirrors may be formed in an aspheric surface.

If up to five mirrors are aspherical, simple manufacturing is possible compared to the embodiment of the present invention in which all mirrors are formed aspheric.

It is particularly preferable if the mirror having the effective range furthest from the optical axis, generally the fourth mirror, is formed into a spherical surface.

The present invention is applied to a projection exposure apparatus in addition to the projection objective lens. The projection exposure apparatus includes an illumination device for illuminating a ring field and a projection objective lens according to the present invention.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail.

Figure 1 shows the effective range and what the diameter of the effective range means in the present application.

1 shows an elongate field, for example in an illuminated field 1 on a projection objective mirror. This type of microlithography of the objective lens according to the present invention.

-When used in a projection exposure apparatus, the form of the effective range. The circle 2 completely surrounds the stretch form and meets the stretch form edge 10 and at two points 6, 8. The circle is always the smallest circle that covers the effective range. The diameter D of the effective range is given from the diameter of the circle 2.

2 shows the object field 11 of the projection exposure apparatus in the object plane of the projection objective lens. The object field is imaged on an image plane on which a photosensitive object, such as a wafer, is disposed by the projection objective lens according to the present invention. The image field in the image plane has the same shape as the object field. The object field or phase field 11 has a segment shape of a ring field. The segment has an axis of symmetry 12.

Also shown in FIG. 2 are the axes defining the object plane, ie the x-axis and the y-axis. As shown in FIG. 2, the axis of symmetry 12 of the ring field 11 extends in the direction of the y-axis. At the same time the y-axis coincides with the scan direction of the EUV-projection exposure apparatus designed as a ring field scanner. The x-direction is the direction perpendicular to the scan direction inside the object plane. The ring field has a so-called average ring field radius R. The radius is determined by the distance between the center point 15 of the image field and the optical axis HA of the projection objective lens.

3 shows two mirror segments 20, 22 of a projection objective according to the invention, for example in the whole system. Mirror segments 20 and 22 correspond to the effective range of the mirror. The mirror segment is disposed along the optical axis 24. As shown in Fig. 3, one constituent space 26, 28 is allocated to the effective ranges 20, 22 of the mirror of the projection objective lens, respectively. In the present application, the depth T of the construction space means the width of the construction space from the center point 30, 32 of the effective range 20, 22 of each mirror parallel to the optical axis. In the present application, the center point of the effective range means the collision point of the chief ray CR of the center point of the object field in the effective range of each mirror. As shown in Fig. 3, the mirror is disposed on the projection objective so that the constituent spaces 26 and 28 do not geometrically invade each other.

4 shows a first embodiment of a six mirror system according to the invention. The size of the object to be imaged, i.e. the object forming a segment of the ring field and having an axis of symmetry as shown in FIG. 2, is at least 20 mm, preferably 25 mm, in the direction perpendicular to the axis of symmetry. The object to be imaged is disposed on the object plane 100 of the objective lens shown in FIG. 4. In this embodiment, as the object field, a ring field segment is formed in the object plane 100. In addition, an object to be imaged on the photosensitive layer (called a reticle in lithography) is disposed in the object plane.

The plane in which the object 100 is formed by the projection objective lens according to the present invention is an image plane 102, and for example, a wafer may be disposed on the image plane 102. The projection objective lens according to the present invention comprises a first mirror S1, a second mirror S2, a third mirror S3, a fourth mirror S4, a fifth mirror S5, and a sixth mirror S6. Include. In the embodiment shown in FIG. 4, a total of six mirrors S1, S2, S3, S4, S5, and S6 are formed as aspherical mirrors. As the first mirror S1, a convex mirror is used.

In the first embodiment according to FIG. 4, the diaphragm B is disposed on the second mirror S2. The system is centered about the optical axis HA and is telecentric in the upper plane, ie in the upper plane 102. The telecentric means that the chief ray CR strikes the image plane 102 at an angle of approximately or approximately 90 degrees.

In order to minimize the light loss and coating induced wavefront aberration inside the mirror system, the angle at which the chief ray CR of the field center point hits each mirror surface is always less than 18 °. 4 shows the constituent spaces B1, B2, B3, B4, B5 and B6 of the effective ranges N1, N2, N3, N4, N5 and N6 of the respective mirrors S1, S2, S3, S4, S5 and S6. ) Is shown.

As clearly shown in FIG. 4, the entire objective lens has all planes B1, B2, B3, B4, B5 and B6 without intersecting the space of another mirror or the optical path in the objective lens. And extend in a direction parallel to the axis of symmetry 12 of the object field lying in the. The coordinate system (x, y, z) is shown in FIG. 4 for easy readability. The optical axis of the objective lens extends in the z-direction, the object field lies in the x-y-object plane and the axis of symmetry of the object field 100 points in the y-direction.

As shown in FIG. 4, all effective range construction spaces may extend in the direction of the axis of symmetry 12 of the object field. This ensures that the mirror is accessed from at least one side of the objective lens and for example inserted and assembled.

In addition, in Embodiment 1 according to FIG. 4, a system having an intermediate phase Z is dealt with. The intermediate image Z is geometrically formed between the fourth mirror S4 and the fifth mirror S5 after the first mirror S1. By means of the intermediate phase Z a first partial system in which the system according to FIG. 4 comprises two partial systems, namely mirrors S1, S2, S3 and S4, and a second partial system comprising mirrors S5, S6 Divided by.

The constituent spaces B1 to B4 and B6 of the mirrors S1 to S4 and S6 are at least 50 mm, and the constituent space B5 of the fifth mirror is at least the effective range diameter of the fifth mirror. Since 1/3 is, the free working distance between the fifth mirror S5 closest to the wafer and the image plane 102 is at least 12 mm.

The code V-data of the first embodiment according to FIG. 4 is presented in Table 1 attached. Where the element numbers are represented by (1), (2), (3), (4), (5), (6) and the mirrors are (S1), (S2), (S3), (S4), ( S5) and (S6).

Both numerical apertures of the system according to Example 1 are 0.25.

5 shows a second embodiment of the present invention. Parts identical to those shown in FIG. 4 have the same reference numerals. Although a total of six mirror surfaces are aspherical, unlike the embodiment according to FIG. 4, the first mirror S1 is formed as a concave mirror rather than a convex mirror.

The data of the system is shown in the code V-table shown in Table 2 attached to this application. The numerical aperture of the projection objective lens according to Fig. 5 is NA = 0.25 as in the first embodiment according to Fig. 4.

In the embodiment according to FIG. 5, the diameter D of the effective range of all the mirrors disposed in the objective lens according to the invention is smaller than 300 mm, and the object to be imaged is a segment of the ring field as shown in FIG. 2.

The effective range in the x-y plane of each mirror of the second embodiment according to FIG. 5 is shown in FIGS. 6A-6F. All figures show an x-y coordinate system defined by the object plane. Here, the y-direction is the scan direction of the ring field scanner, and the x-direction is the direction perpendicular to the scan direction.

As shown in FIG. 6A, the effective range N1 on the mirror S1 is actually elongated and has a diameter D as defined in FIG. 1 of 145.042 mm. The effective range N2 on the mirror S2 is actually circular and the diameter is 157.168 mm according to FIG. 6B.

The effective range N3 on the mirror S3 is also elongated and the diameter is 102.367 mm according to FIG. 6C. The effective range N4 on the mirror S4 has a diameter of 222.497 mm according to FIG. 6D.

The effective ranges N5 and N6 on the mirrors S5 and S6 are actually circular according to FIGS. 6E and 6F, the diameter D of the effective range N5 being 83.548 mm and the diameter of the effective range N6. Is 270.054 mm.

In accordance with the present invention, the diameters of all the effective ranges N1 to N6 of the projection objective lens embodiment are smaller than 300 mm according to FIG. 5.

7 shows a third embodiment of the projection objective lens according to the invention with six aspherical mirrors. The same parts as in FIGS. 4 and 6 have the same reference numerals. The data of the third embodiment according to FIG. 7 is presented in code V-format in the attached Table 3. The numerical aperture of the system according to FIG. 7 is NA = 0.25. The first mirror S1 of the embodiment according to FIG. 7 is formed in a plane near the axis. In the present application, the basic curvature of the mirror S1 near the optical axis HA is zero.

8 shows a particularly preferred six mirror system from a manufacturing standpoint. In the system according to FIG. 8 the numerical aperture is 0.23 and the fourth mirror is a spherical mirror, which is very preferred from a manufacturing point of view. This is because the spherical surface can be processed more easily than the aspherical surface, and the fourth mirror S4 is a mirror having an effective range farthest from the optical axis.

The data of the system according to FIG. 8 is presented in code V-format in the attached Table 4.

The relatively small dimension of the effective range of the mirror, in particular the fourth mirror, is given by the position of the fourth mirror geometrically between the third and second or first and second mirrors in the projection objective.

Data relating to the position of the second and first mirrors or the fourth mirror with respect to the second and third mirrors is represented by the following conditions.

0.1 < <0.9 (1)

0.3 < <0.9 (2)

Preferably it applies to condition (2):

0.4 < <0.9 (2a)

In four examples, the conditions are shown in the table below.

Table 5: Data for Condition (1)

Example characteristic (S4S1) / (S2S1) 1 = Figure 4 M1 convex 0.14 2 = FIG. 5 M1 concave 0.35 3 = Figure 7 M1 flat 0.19 4 = Figure 8 NA = 0.23, 5 aspherical 0.67

Table 6: Data for Condition (2)

Example characteristic (S3S4) / (S2S3) 1 = Figure 4 M1 convex 0.31 2 = FIG. 5 M1 concave 0.44 3 = Figure 7 M1 flat 0.34 4 = Figure 8 NA = 0.23, 5 aspherical 0.69

The diameter of the effective range is a particularly important parameter because it determines the dimensions of the objective chamber. Large coverage and therefore large mirrors require very large construction spaces, which is undesirable from the standpoint of evacuating large UHV-systems. Another disadvantage of a large mirror is its high sensitivity to mechanical vibrations because its natural frequency is smaller than in small mirrors. Another advantage of mirrors with small dimensions is that aspherization and coating of the substrate can be made in a small UHV-processing chamber.

Since coating of a mirror substrate with a multi-layer system causes layer stress, deformation may appear, especially at the edges of the substrate. In order for the deformation not to extend within the effective range of the mirror, it is necessary to provide a minimum area outside the effective range that can reduce the deformation. The boundary regions of the individual mirrors in Examples 1-4 are shown in Table 7 below.

Table 7: Data for boundary regions of mirrors S1 to S6

mirror A1 = FIG. 4 A2 = FIG. 5 A3 = Figure 7 A4 = Figure 8 S1 13 mm 21 mm 16 mm 2 mm S2 11 mm 11 mm 8 mm 8 mm S3 22 mm 28 mm 26 mm 8 mm S5 4 mm 4 mm 4 mm 5 mm S6 5 mm 6 mm 5 mm 2 mm

As shown in the table, in the embodiment according to FIGS. 4, 5 and 7 the boundary area for each mirror is larger than 4 mm, which is particularly preferred when considering layer stress.

Figure 9 shows the arrangement of the fifth and sixth mirrors S5, S6 in a preferred embodiment of the projection objective lens according to the present invention.

According to FIG. 9, the light beam 200 telecentrically strikes, for example, the image plane 102 on which the wafer is placed. The sixth mirror S6 is formed concave. The fifth mirror S5 lies between the sixth mirror S6 and the image plane 102. In the projection objective lens according to the present invention, all the mirrors S1, S2, S3, S4, S5, and S6 are disposed between the object plane 100 and the image plane 102. If a shadowless optical path is required in the projection objective according to the invention, in the objective lens portion of the image side with the mirrors S5 and S6, shown in Fig. 9, two critical regions for the shadowless ray guide are provided. exist.

One of the critical regions lies at the upper edge 202 of the effective range of the fifth mirror S5. The light guide (guide) should be configured such that the lower edge light ray 204 of the light beam 200 extends above the effective range N5 of the mirror S5 and impinges on the image plane 102. If R represents the ring field radius and S5 B represents the distance between S5 and the image plane 102, then the distance between the lower edge light ray 204 and the optical axis HA is given by the following equation.

y = R-(S5B) * tan (arc sin (NA))

In the above formula, NA is the numerical aperture in the exit pupil.

The upper limit of the effective range N5 is determined by the collision point of the upper edge ray 206 of the light beam 200 with respect to the fifth mirror S5. Using the following variables

r ₆ : radius of curvature of S6

(S5 S6): (Positive) distance between S5 and S6

The focus intercept equation is applied to the sixth mirror with respect to the distance y 'of the optical axis HA' and the upper edge 202 of the effective range N% of the fifth mirror.

In order to obtain a shadowless ray at the fifth mirror S5, the following equation should be applied:

Δy = y-y'≥0

Another critical range lies at the bottom edge of S6. Here, the focal intercept equation is applied twice to mirrors S5 and S6 with respect to the ring field radius R of the image field in the image plane 102 in order to approximate the shadow paraxial approximation.

particularly if r ₆ , r ₅ , (S ₅ B) and (S ₅ S ₆ ) are fixedly selected, then r ₆ = 535.215 mm; r ₅ = 594.215 mm; (S5B) = 44.083 mm; (S5S6) = 437.186 mm, from the above equation for the ring field radius (R) along the opening under boundary conditions for light guide without guidance in the fifth mirror according to the equations for y 'and Δy: Is obtained:

Table 5

NA 0.15 0.20 0.25 0.30 R (mm) 18.191 24.475 30.958 37.707

As shown in Table 5, the large numerical aperture in the exit pupil results in a large ring field radius.

In a coaxial 6-mirror-objective, when the ring field radius is given in advance, numerical aperture enlargement is only possible up to a certain value. If the value is exceeded, the aspherical surface in the fifth mirror is almost jumped. This increase leads to problems in aspherical fabrication and aspheric measurement techniques and problems in the correction of objective lenses.

S5B is equal to the so-called working distance of the objective lens on the wafer that should not be below the minimum value. The reduction of the ring field radius by the reduction of (S5 B) is only possible until the minimum distance is reached.

Reduction of the distance S5 S6 causes a reduction of the ring field radius, but enlarges the angle of incidence to the fifth mirror S5. The large angle of incidence on (S5) allows the fabrication of a multilayer system with the best reflectance at very high cost. The reduction in r ₅ causes the same disadvantages as the reduction in distance S5 S6, since this reduction is represented by a large angle of incidence on (S5).

Magnification of r ₆ reduces the ring field radius, but the shading removal at the fifth mirror is lowered.

10 shows a projection exposure apparatus for microlithography with six mirror-projection objectives 200 in accordance with the present invention. The lighting device 202 may be formed, for example, as "illumination system especially for EUV-lithography" of EP 99106348 or "Illumination system particularly for EUV-Lithography" of US patent 09 / 305,017. The disclosure of this patent may be referred to in this application, such an illumination system comprises an EUV-light source A first mirror 207 comprising a grid element (so-called field honeycomb), a grid element (so-called, The reticle 212 is illuminated by a second mirror 208 comprising an aperture stop honeycomb, and a mirror 210. The light reflected by the reticle 212 is photosensitive by the projection objective according to the invention. The image is formed on the support 214 including the layer.In the chip manufacturing process, the projection exposure apparatus for microlithography according to the present invention can be used in the exposure process of the lithography process.

The present invention provides a projection objective with six mirrors, which is characterized by an effective range with small dimensions in all mirrors and forms a compact projection objective which is particularly desirable in terms of construction and manufacturing techniques.

Attachment: Table 1-4 Code V-Objective Data

Table 1: Example 1 (Figure 4)

Table 2: Example 2 (Figure 5)

Table 3: Example 3 (Figure 7)

Table 4: Example 4 (Figure 8)

1 is a schematic diagram showing the effective range of a mirror.

2 is a schematic diagram showing a ring field in the object plane of an objective lens;

3 is a schematic diagram defining the construction space for two arbitrary mirrors of a projection objective;

4 shows a first embodiment of a projection objective lens according to the invention with six aspherical mirrors in which the first mirror is convex;

Fig. 5 is a second embodiment of the projection objective lens according to the invention with six aspherical mirrors in which the first mirror is concave;

6A-6F are schematic views showing the effective range of a total of six mirrors of the projection objective lens according to FIG.

7 shows a third embodiment of a projection objective according to the invention with six aspherical mirrors in which the first mirror is formed in the paraxial plane.

8 shows a fourth embodiment of a projection objective according to the invention, with five aspherical mirrors and one spherical mirror, for example a fourth mirror formed into a spherical surface.

9 is a schematic diagram showing regions of the fifth and sixth mirrors of a six-mirror objective lens according to the present invention;

Fig. 10 is a schematic diagram showing the basic configuration of a projection exposure apparatus with an objective lens according to the present invention.

* Description of the symbols for the main parts of the drawings *

11: object field 20, 22: mirror segment

26, 28: construction space 100: object plane

102: image plane 200: light beam

204: lower edge ray 206: upper edge ray

S1, S2, S3, S4, S5, S6: Mirror

N1, N2, N3, N4, N5, N6: Effective Range

HA: optical axis NA: numerical aperture

Claims (51)

An entrance pupil and an exit pupil for projecting an object field in the object plane from the image plane to an upper field representing a segment of the ring field, the segment having a width perpendicular to the axis of symmetry and the axis of symmetry, the width being at least 20 mm ego, The first (S1), the second (S2), and the third (S1), the second (S2) and the third ( A short wavelength microlithography projection objective comprising S3), fourth (S4), fifth (S5) and sixth mirrors (S6) and an optical axis, The diameters of the effective ranges of the first, second, third, fourth, fifth, and sixth mirrors depend on the numerical aperture NA of the objective lens in the exit pupil. Diameter of effective range ≤ 1200 mm * NA Microlithographic projection objective, characterized in that is applied. The method of claim 1, The numerical aperture in the exit pupil is greater than 0.1, And a diameter of the effective range of said first, second, third, fourth, fifth and sixth mirrors ≤ 300 mm. The method according to claim 1 or 2, The first, second, third, fourth, fifth and sixth mirrors each include a rear space having a depth in an effective range parallel to the optical axis measured from the mirror front face. The depth of the third, fourth and sixth spaces is at least 50 mm, the depth of the space of the fifth mirror is greater than one third of the diameter value of the fifth mirror, and the respective spaces do not intrude into each other. Characterized by microlithography projection objectives. The method of claim 3, wherein A microlithographic projection objective, wherein the space of all mirrors can extend in a direction parallel to the axis of symmetry without intersecting the space of another mirror or the optical path in the objective lens. The method of claim 4, wherein The first, second, third, fourth, fifth, and sixth mirrors include a boundary area surrounding the effective range, the boundary area is larger than 4 mm, and light is blocked by the objective lens. A microlithographic projection objective characterized in that it is guided without. The method according to claim 1 or 2, And the effective range of the fourth mirror is geometrically arranged between the second mirror and the image plane. The method according to claim 1 or 2, And the fourth mirror is geometrically disposed between the third mirror and the second mirror. The method according to claim 1 or 2, And the fourth mirror is geometrically disposed between the first mirror and the second mirror. The method according to claim 1 or 2, The distance S4 S1 of the vertex of the fourth mirror and the first mirror along the optical axis to the distance S2 S1 of the second mirror and the first mirror 0.1 < <0.9 A microlithographic projection objective characterized in that it lies in the range of. The method according to claim 1 or 2, The distance (S2 S3) of the vertex of the third mirror and the second mirror along the optical axis is the distance (S3 S4) of the fourth mirror and the third mirror 0.3 < <0.9 A microlithographic projection objective characterized in that it lies in the range of. The method according to claim 1 or 2, The numerical aperture NA in the exit pupil, the distance (S5 S6) of the vertex of the fifth mirror and the sixth mirror along the optical axis, the distance (S5 B) of the vertex of the fifth mirror and the image plane, of the fifth or sixth mirror The average ring field radius R depends on the radius of curvature r ₅ , r ₆ Microlithographic projection objective, characterized in that applied. The method according to claim 1 or 2, A microlithographic projection objective wherein the angle of incidence of the chief rays of field points lying on the axis of symmetry at the center of the object field is less than 18 ° for all mirrors. The method according to claim 1 or 2, And an intermediate image formed after the fourth mirror (S4) in the light direction in the projection objective lens. The method according to claim 1 or 2, A microlithographic projection objective characterized in that an aperture (B) is arranged in an optical path on a second mirror (S2). The method according to claim 1 or 2, And said first mirror is a convex mirror and said first, second, third, fourth, fifth and sixth mirrors are formed aspheric. The method according to claim 1 or 2, And the first, second, third, fourth, fifth, and sixth mirrors are aspheric, wherein the first mirror is flat near the axis. The method according to claim 1 or 2, And said first mirror is a concave mirror and said first, second, third, fourth, fifth and sixth mirrors are formed aspheric. The method according to claim 1 or 2, And all the mirrors are formed aspheric. The method according to claim 1 or 2, A microlithographic projection objective wherein up to five mirrors are aspherical. The method of claim 19, And said fourth mirror is formed as an aspherical surface. The method according to claim 1 or 2, And said second to sixth mirrors (S2-S6) are formed in the order of concave mirror-convex mirror-concave mirror-convex mirror-concave mirror. In microlithography projection objective apparatus, 3. A microlithographic projection objective lens apparatus according to claim 1 or 2, wherein said objective lens is telecentric in an image side plane. In the projection exposure apparatus, A projection exposure apparatus comprising an illumination device for illuminating a ring field as well as the projection objective lens according to claim 1. In the chip manufacturing method which performs an exposure process using a projection exposure apparatus in a lithography process, A method of manufacturing a chip, characterized in that the reticle is illuminated and formed on the photosensitive layer using the projection exposure apparatus according to claim 23. In microlithography projection objective apparatus, 3. The microlithographic projection objective lens apparatus of claim 1 or 2, wherein the short wavelength is less than or equal to 193 nm. In microlithography projection objective apparatus, The numerical aperture of the exit pupil in the objective lens according to claim 1 or 2 is greater than 0.2, and the diameter of the effective range of the first, second, third, fourth, fifth and sixth mirrors ≤ 300 A microlithography projection objective device, characterized in that it is mm. In microlithography projection objective apparatus, The numerical aperture of the exit pupil in the objective lens according to claim 1 or 2 is larger than 0.23, and the diameter of the effective range of the first, second, third, fourth, fifth and sixth mirrors ≤ 300 A microlithography projection objective device, characterized in that it is mm. Having an entrance pupil and an exit pupil for projecting an object field in the object plane from the image plane to an upper field representing a segment of the ring field, the segment having a width perpendicular to the axis of symmetry and the axis of symmetry, the width being at least 25 mm. ego, The first (S1), the second (S2), and the third (S1), the second (S2) and the third ( A short wavelength microlithography projection objective comprising S3), fourth (S4), fifth (S5) and sixth mirrors (S6) and an optical axis, The diameters of the effective ranges of the first, second, third, fourth, fifth, and sixth mirrors depend on the numerical aperture NA of the objective lens in the exit pupil. Diameter of effective range ≤ 1200 mm * NA applies, Wherein said first, second, third, fourth, fifth, and sixth mirrors each comprise a rear space having a depth in an effective range parallel to the optical axis measured from the mirror front face; The depth of the second, third, fourth and sixth spaces is at least 50 mm, the depth of the space of the fifth mirror is greater than one third of the diameter value of the fifth mirror, and the respective spaces do not intrude into each other Microlithography projection objective. The method of claim 28, The numerical aperture in the exit pupil is greater than 0.1, And a diameter of the effective range of said first, second, third, fourth, fifth and sixth mirrors ≤ 300 mm. The method of claim 28 or 29, And the effective range of the fourth mirror is geometrically arranged between the second mirror and the image plane. The method of claim 28 or 29, And the fourth mirror is geometrically disposed between the third mirror and the second mirror. The method of claim 28 or 29, And the fourth mirror is geometrically disposed between the first mirror and the second mirror. The method of claim 28 or 29, The distance S4 S1 of the vertex of the fourth mirror and the first mirror along the optical axis to the distance S2 S1 of the second mirror and the first mirror 0.1 < <0.9 A microlithographic projection objective characterized in that it lies in the range of. The method of claim 28 or 29, The distance (S2 S3) of the vertex of the third mirror and the second mirror along the optical axis is the distance (S3 S4) of the fourth mirror and the third mirror 0.3 < <0.9 A microlithographic projection objective characterized in that it lies in the range of. The method of claim 28 or 29, The numerical aperture NA in the exit pupil, the distance (S5 S6) of the vertex of the fifth mirror and the sixth mirror along the optical axis, the distance (S5 B) of the vertex of the fifth mirror and the image plane, of the fifth or sixth mirror The average ring field radius R depends on the radius of curvature r ₅ , r ₆ Microlithographic projection objective, characterized in that applied. The method of claim 28 or 29, A microlithographic projection objective wherein the angle of incidence of the chief rays of field points lying on the axis of symmetry at the center of the object field is less than 18 ° for all mirrors. The method of claim 28 or 29, And an intermediate image formed after the fourth mirror (S4) in the light direction in the projection objective lens. The method of claim 28 or 29, A microlithographic projection objective characterized in that an aperture (B) is arranged in an optical path on a second mirror (S2). The method of claim 28 or 29, And said first mirror is a convex mirror and said first, second, third, fourth, fifth and sixth mirrors are formed aspheric. The method of claim 28 or 29, And the first, second, third, fourth, fifth, and sixth mirrors are aspheric, wherein the first mirror is flat near the axis. The method of claim 28 or 29, And said first mirror is a concave mirror and said first, second, third, fourth, fifth and sixth mirrors are formed aspheric. The method of claim 28 or 29, And all the mirrors are formed aspheric. The method of claim 28 or 29, A microlithographic projection objective wherein up to five mirrors are aspherical. The method of claim 43, And said fourth mirror is formed as an aspherical surface. The method of claim 28 or 29, And said second to sixth mirrors (S2-S6) are formed in the order of concave mirror-convex mirror-concave mirror-convex mirror-concave mirror. In microlithography projection objective apparatus, 30. A microlithographic projection objective lens apparatus according to claim 28 or 29, wherein said objective lens is telecentric in an image side plane. In the projection exposure apparatus, 30. A projection exposure apparatus, wherein the projection exposure apparatus comprises an illumination device for illuminating the ring field as well as the projection objective lens according to claim 28. In the chip manufacturing method which performs an exposure process using a projection exposure apparatus in a lithography process, 48. A method of manufacturing a chip, wherein the reticle is illuminated and imaged on the photosensitive layer using the projection exposure apparatus according to claim 47. In microlithography projection objective apparatus, 30. A microlithographic projection objective lens apparatus according to claim 28 or 29, wherein said short wavelength is less than or equal to 193 nm. In microlithography projection objective apparatus, The numerical aperture of the exit pupil in the objective lens according to claim 28 or 29 is greater than 0.2, and the diameter of the effective range of the first, second, third, fourth, fifth and sixth mirrors ≤ 300 A microlithography projection objective device, characterized in that it is mm. In microlithography projection objective apparatus, The numerical aperture of the exit pupil in the objective lens according to claim 28 or 29 is greater than 0.23, and the diameter of the effective range of the first, second, third, fourth, fifth and sixth mirrors ≤ 300 A microlithography projection objective device, characterized in that it is mm.